Visual bug in copper grates

There is a bug where you can see the surface of a copper grate through a copper grate of a different oxidation state.

Steps to reproduce:

• Place a copper grate
• Place another copper grate of a different oxidation state adjacent to it.
• You can see the edge of the copper grate while looking through it, inconsistent with not being able to see the edge if the 2 blocks were to be identical.